Interpretation of vaccine associated neurological adverse events: a methodological and historical review

Abstract

As a result of significant recent scientific investment, the range of vaccines available for COVID-19 prevention continues to expand and uptake is increasing globally. Although initial trial safety data have been generally reassuring, a number of adverse events, including vaccine induced thrombosis and thrombocytopenia (VITT), have come to light which have the potential to undermine the success of the vaccination program. However, it can be difficult to interpret available data and put these into context and to communicate this effectively. In this review, we discuss contemporary methodologies employed to investigate possible associations between vaccination and adverse neurological outcomes and why determining causality can be challenging. We demonstrate these issues by discussing relevant historical exemplars and explore the relevance for the current pandemic and vaccination program. We also discuss challenges in understanding and communicating such risks to clinicians and the general population within the context of the ‘infodemic’ facilitated by the Internet and other media.

Acute Unilateral Peripheral Vestibulopathy After COVID-19 Vaccination: Initial Experience in a Tertiary Neurotology Center

“…To obtain more representative and reliable results about a possible link between COVID-19 vaccination and the rare event of an AUPVP, large-scale, multi-center studies are warranted. In this context, self-controlled case series (SCCS) offer a valuable approach because each subject acts as its own control, thus minimizing the effect of possible confounders (6). Furthermore, these studies should comprise follow-up vestibular laboratory testing in order to determine the prognosis of AUPVP after COVID-19 vaccination as compared to other AUPVP cases.…”

“…While temporal association does not prove causality, it is nevertheless important to make note of such cases and report them to the health authorities. Based on these data, large-scale post-authorization studies can be conducted to re-evaluate the safety of a vaccine and to re-weigh the risk-benefit-ratio of vaccinations for specific subgroups of the population (6,7).…”

Alteraciones hematológicas como consecuencia de COVID-19 y sus vacunas

“…Sin embargo, también se han reportado reacciones adversas con la combinación de vacunas, pero a la vez, parece tener como resultado positivo una mejor inmunidad. Adicionalmente, se reporta que hay mayor riesgo en los menores de 60 años y en las mujeres [44,45]. En cuanto a comorbilidades, no hay estudios definitivos aún, pero se ha observado una mayor frecuencia en aquellos individuos con factores de riesgo cardiovascular como obesidad, hábito del cigarrillo, hipertensión o diabetes [35].…”

Benign Fasciculation Syndrome and Migraine Aura without Headache: Possible Rare Side Effects of the BNT162b2 mRNA Vaccine? A Case Report and a Potential Hypothesis

“…Thus far, several neurological AEFIs related to the BNT162b2 vaccine have been reported, some examples of which are Bell's palsy, Guillain Barre syndrome, multiple sclerosis-like central nervous system demyelination syndrome and rhombencephalitis, as well as functional neurological disorders. The pathophysiological mechanisms for these phenomena in potential relation to the vaccine are still mostly unknown [4][5][6][7][8][9][10][11]. Luckily, preliminary data indicate that neurological complications from SARS-CoV-2 vaccines are rare in incidence [12].…”